Comparative performance of chemically and enzymatically modified whey proteins

Alternative approaches for enhancing the utilization of whey proteins were investigated. Chemical and enzymatic treatments were applied to induce some structural and electrostatic changes in the whey proteins. Chemical modification involved covalent attachment of succinyl and acetyl groups to the free amino sites of lysine residues. Enzymatic modification included deamidation of these active sites via trypsin and chymotrypsin under conditions unfavorable for potent proteolysis. Chemical treatments, in particular succinylation, resulted in better emulsifying capability and stability as evidenced by a well-balanced distribution of oil droplets within the emulsion ultrastructure. Foaming ability and stability were substantially enhanced by both treatments, although the effect was stronger in the chemically-treated proteins. Enzyme-treated whey proteins, however, showed superior solubility and in-vitro digestibility as compared to their chemically treated or native counterparts. In a simulated intermediate moisture food system, succinylation offered the best protective effect against browning development and loss of basic amino acids.